#!/usr/bin/env python3
from __future__ import annotations

import argparse
import gzip
import os.path
import shutil
import subprocess
import tarfile
import tempfile
from collections.abc import Sequence


# This is a script for generating the tarred resources for git repo
# dependencies.  Currently it's just for "vendoring" ruby support packages.


REPOS = (
    ('rbenv', 'https://github.com/rbenv/rbenv', '38e1fbb'),
    ('ruby-build', 'https://github.com/rbenv/ruby-build', 'ed384c8'),
    (
        'ruby-download',
        'https://github.com/garnieretienne/rvm-download',
        '09bd7c6',
    ),
)


def reset(tarinfo: tarfile.TarInfo) -> tarfile.TarInfo:
    tarinfo.uid = tarinfo.gid = 0
    tarinfo.uname = tarinfo.gname = 'root'
    tarinfo.mtime = 0
    return tarinfo


def make_archive(name: str, repo: str, ref: str, destdir: str) -> str:
    output_path = os.path.join(destdir, f'{name}.tar.gz')
    with tempfile.TemporaryDirectory() as tmpdir:
        # this ensures that the root directory has umask permissions
        gitdir = os.path.join(tmpdir, 'root')

        # Clone the repository to the temporary directory
        subprocess.check_call(('git', 'clone', repo, gitdir))
        subprocess.check_call(('git', '-C', gitdir, 'checkout', ref))

        # We don't want the '.git' directory
        # It adds a bunch of size to the archive and we don't use it at
        # runtime
        shutil.rmtree(os.path.join(gitdir, '.git'))

        arcs = [(name, gitdir)]
        for root, dirs, filenames in os.walk(gitdir):
            for filename in dirs + filenames:
                abspath = os.path.abspath(os.path.join(root, filename))
                relpath = os.path.relpath(abspath, gitdir)
                arcs.append((os.path.join(name, relpath), abspath))
        arcs.sort()

        with gzip.GzipFile(output_path, 'wb', mtime=0) as gzipf:
            with tarfile.open(fileobj=gzipf, mode='w') as tf:
                for arcname, abspath in arcs:
                    tf.add(
                        abspath,
                        arcname=arcname,
                        recursive=False,
                        filter=reset,
                    )

    return output_path


def main(argv: Sequence[str] | None = None) -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument('--dest', default='pre_commit/resources')
    args = parser.parse_args(argv)
    for archive_name, repo, ref in REPOS:
        print(f'Making {archive_name}.tar.gz for {repo}@{ref}')
        make_archive(archive_name, repo, ref, args.dest)
    return 0


if __name__ == '__main__':
    raise SystemExit(main())
